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Hygrothermal Failure Case Study: Fergusson School

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Abstract
INSULATED ROOFS THAT are insulated above the purlins and contain a vapor-control layer (VCL) are a new technology in New Zealand, and these types of roofs need more in-depth hygrothermal modeling than was required for-traditional (insulation at the ceiling level) vapor-leaky roof systems that were used in the past. Over the last decade, the addition of more insulation into traditional roof systems has become a trend in New Zealand as owners aim to increase occupancy comfort, improve health, and reduce energy consumption. However, such efforts may lead to condensate problems in the roof layers, as discussed in more depth in later sections.
Date
2/2026
Author(s)
Dave Edkins
Page(s)
26-32
Keyword(s)
insulated; roof; vapor; layer


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